With the recent developments in studies to elucidate physiological actions and functions of carbohydrates, various useful saccharides have been found, and great concern has been directed particularly toward various oligosaccharides which are formed by glycosyltransferase, such as fructo-oligosaccharide, soy bean oligosaccharide, galacto-oligosaccharide, xylo-oligosaccharide, gentio-oligosaccharide, lactosucrose, coupling sugar and paratinose. Oligosaccharides are used not only as simple sweeteners but also as diet sweeteners by utilizing their anti-dental caries property or hardly digestible property to inhibit digestion and absorption of food as energy source. They are also used, for example, in foods for specified health use, with the aim of improving intestinal bacterial flora and improving physical conditions such as prevention of constipation or diarrhea and acceleration of peristalsis of the intestines, because they are used as nutrient sources by lactobacteria and bifidobacterium and can control intestinal environment, so that their physiological activities are drawing attention.
Oligosaccharides have been conventionally prepared by various methods. That is, they are produced in the industrial scale making use of various types of hydrolase, transferase, etc. As the method for supplying the oligosaccharides thus prepared into the living body, they are contained as the component in food materials such as carbonated drinks, soft drinks, table sugar, fermented milk, candies, biscuits and chocolate so as to exhibit their various physiological activities in the living body by the ingestion of such food materials, or these oligosaccharides are directly ingested.
However, when such various food materials are blended with these oligosaccharides, such application has many problems such as a high possibility of inhibiting taste, flavor and eating touch of the food materials and a necessity to select an oligosaccharide suited for each food material. In other words, positive ingestion of these oligosaccharides cannot satisfy the diversity of dietary life because of the necessity to selectively ingest a food material containing an oligosaccharide of interest.